Such a heel holder is disclosed in German Offenlegungsschrift No. 23 40 416 (corresponds to U.S. Pat. No. 3,964,757). In this heel holder, the stepping spur is constructed as a two-arm lever. The back side of this lever carries a controlling cam which can engage a projection on a slide member, the projection serving as a locking member and the slide member being biased by the locking spring. When the projection is in the region of the stepping spur which lies above its swivel axis, which corresponds with the skiing position of the heel holder, then the stepping spur does not engage the ski shoe. However, when the projection engages the region of the controlling cam of the stepping spur which is below the swivel axis, then the stepping spur is pressed by the locking spring against the underside of the ski shoe. The contact between the stepping spur and ski shoe therefore occurs with friction.
This embodiment of a stepping spur has various disadvantages. For example, it cannot be easily applied to all heel holders, but only to those in which the locking member biased by the locking spring is arranged on a piston which is movable parallel to the upper side of the ski. Furthermore, the ski shoe must be provided on a relatively thick base plate in order to make possible a swivelling of the stepping spur relative to the upper side of the ski without the upper side of the ski being provided with a recess. Finally, the axis of the stepping spur is exposed to the full pressure of the locking spring, which leads to rapid wear of the heelholder.
In a different heel holder, the stepping spur is guided movably along the wall of the binding housing which faces the ski shoe (all Austrian Pat. No. 287 553), which corresponds to U.S. Pat. No. 3,554,571. The stepping spur is biased by a spring which urges it toward the down-holding arrangement. Due to this spring, the distance between the stepping spur and down-holding arrangement can increase during stepping in and also during an automatic release. In the skiing position of the heel holder, however, the ski shoe is gripped between the stepping spur and the down-holding means by the urging of the spring.
The invention has as one goal to do away with the disadvantages of the known designs and to provide an arrangement of a stepping spur which can be applied in almost all heel holders. The ski shoe in the inventive arrangement, in the skiing position of the heel holder, is to be free of the influence of the stepping spur, but at the start of the stepping-in operation the stepping spur is to be held in a forwardly swung position.